You need to do something else to occupy your mind, Dan. Read, run, draw, pain, go get a freaking children's coloring book and some markers! Believe me, when i was in the psych ward lockdown for detox, the coloring pages and markers were like cigarettes in prison. People who hogged the markers were hated. Anything simple and nonfrustrating to occupy and calm the mind until the urge passes will do. Be creative. Stewing in your own frustration is counter productive.